Investigating the geochemical and physical response to fluid rock reaction beneath an active hydrothermal system in an arc environment.
Lead Research Organisation:
University of Southampton
Department Name: Sch of Ocean and Earth Science
Abstract
What goes on beneath active and extinct hydrothernal vent sites forming within the caldera of a submarine volcano? Establishing the processes active beneath the vent sites is crucial to our understanding of how these vent systems work. Moreover, such systems effectively represent a natural laboratories, which provide insights into the processes widely considered to be responsible for massive sulphide, copper, lead, zinc and gold, mineral resources we find, and presently exploit, from within the geological record. The Brothers volcano is of particular interest, as submarine arc volcanoes differ substantially from those in mid-ocean spreading environments in that they commonly contain a large component of fluid, likley to have derived from the magma chamber below. These magmatic fluids generate contrasting fluid rock reactions which influence the composition and the ore mineral forming potential of the hydrothermal fluids. In addition, these fluids are anticipated to alter the surrounding rocks in a manner not encountered in other environments and which may prove to be distinct signatures that can utimately aid exploration for resources in both submarine and terrestrial environments.
Planned Impact
The research completed within this proposal will:
(1) inform new exploration methodologies to constrain seafloor mineral resources;
(2) provide key information to aid the terrestrial exploration of arc-hosted VMS
(3) communicate directly with industrialists and the science community and the general public, of the benefits and environmental consequences of such exploration and exploitation.
These outcomes will be achieved through a combination of shipboard and post-cruise activities.
Shipboard: IODP Expedition 376 will be fully engaged in maximising the impact of the cruise through the participation of two Education and Outreach officers during the expedition: Peregrin A. Hyde and Tammy J. Orilio. SR has already agreed to actively engage in their activities on board the Joides Resolution, with agreement already in place to contribute to the IODP Expedition 376 Blog, actively use social media, in particular twitter, and engage in classroom at sea activities.
Postcruise: Following the cruise SR will actively engage with UK and international stakeholder groups.
This engagement will take on various forms with industry and the wider scientific community "captured" through dissemination of results in appropriate fora, in particular international conferences and journals that enjoy a substantive industry and academia subscription e.g Society of Economic Geologists Conference (this year Keystone Colorado) and SGA (Society for Geology Applied to Mineral Deposits) with the 2019 conference at Glasgow. It is perhaps noteworthy that the PI's of the expedition (Humphris and de Ronde) are already scheduled to present the initial findings at the Gordon Conference in Boston in August 2018.
Finally, all acquired data will be lodged with National Geoscience Data Centre, to add value and usability into the medium-to-longer term.
(1) inform new exploration methodologies to constrain seafloor mineral resources;
(2) provide key information to aid the terrestrial exploration of arc-hosted VMS
(3) communicate directly with industrialists and the science community and the general public, of the benefits and environmental consequences of such exploration and exploitation.
These outcomes will be achieved through a combination of shipboard and post-cruise activities.
Shipboard: IODP Expedition 376 will be fully engaged in maximising the impact of the cruise through the participation of two Education and Outreach officers during the expedition: Peregrin A. Hyde and Tammy J. Orilio. SR has already agreed to actively engage in their activities on board the Joides Resolution, with agreement already in place to contribute to the IODP Expedition 376 Blog, actively use social media, in particular twitter, and engage in classroom at sea activities.
Postcruise: Following the cruise SR will actively engage with UK and international stakeholder groups.
This engagement will take on various forms with industry and the wider scientific community "captured" through dissemination of results in appropriate fora, in particular international conferences and journals that enjoy a substantive industry and academia subscription e.g Society of Economic Geologists Conference (this year Keystone Colorado) and SGA (Society for Geology Applied to Mineral Deposits) with the 2019 conference at Glasgow. It is perhaps noteworthy that the PI's of the expedition (Humphris and de Ronde) are already scheduled to present the initial findings at the Gordon Conference in Boston in August 2018.
Finally, all acquired data will be lodged with National Geoscience Data Centre, to add value and usability into the medium-to-longer term.
Organisations
People |
ORCID iD |
| Stephen Roberts (Principal Investigator) |
Publications
De Ronde C
(2019)
Critical role of caldera collapse in the formation of seafloor mineralization: The case of Brothers volcano
in Geology
Martin A
(2023)
Hydrothermal Alteration Within the Brothers Submarine Arc Volcano, Kermadec Arc, New Zealand
in Economic Geology
| Description | Hydrothermal systems hosted by submarine arc volcanoes commonly include a large component of magmatic fluid. The high Cu-Au contents and strongly acidic fluids in these systems are similar to those that formed in the shallow parts of some porphyry copper and epithermal gold deposits mined today on land. Two main types of hydrothermal systems occur along the submarine portion of the Kermadec arc (offshore New Zealand): magmatically influenced and seawater-dominated systems. Brothers volcano hosts both types. Here, we report results from a series of drill holes cored by the International Ocean Discovery Program into these two types of hydrothermal systems. We show that the extent of hydrothermal alteration of the host dacitic volcaniclastics and lavas reflects primary lithological porosity and contrasting spatial and temporal contributions of magmatic fluid, hydrothermal fluid, and seawater. We present a two-step model that links the changes in hydrothermal fluid regime to the evolution of the volcano caldera. Initial hydrothermal activity, prior to caldera formation, was dominated by magmatic gases and hypersaline brines. The former mixed with seawater as they ascended toward the seafloor, and the latter remained sequestered in the subsurface. Following caldera collapse, seawater infiltrated the volcano through fault-controlled permeability, interacted with wall rock and the segregated brines, and transported associated metals toward the seafloor and formed Cu-Zn-Au-rich chimneys on the caldera walls and rim, a process continuing to the present day. This two-step process may be common in submarine arc caldera volcanoes that host volcanogenic massive sulfide deposits, and it is particularly efficient at focusing mineralization at, or near, the seafloor. |
| Exploitation Route | Insights into hydrothermal ore formation in volcanic systems - important information for exploration geologists |
| Sectors | Education,Environment,Other |
| URL | http://publications.iodp.org/proceedings/376/376title.html |